C H A P T E R
10
Configuring IEEE 802.1x Port-Based
Authentication
This chapter describes how to configure IEEE 802.1x port-based authentication on the Catalyst 3750
switch. IEEE 802.1x authentication prevents unauthorized devices (clients) from gaining access to the
network. Unless otherwise noted, the term switch refers to a standalone switch and to a switch stack.
Note
For complete syntax and usage information for the commands used in this chapter, see the “RADIUS
Commands” section in the Cisco IOS Security Command Reference, Release 12.2 and the command
reference for this release.
This chapter consists of these sections:
•
Understanding IEEE 802.1x Port-Based Authentication, page 10-1
•
Configuring IEEE 802.1x Authentication, page 10-20
•
Displaying IEEE 802.1x Statistics and Status, page 10-41
Understanding IEEE 802.1x Port-Based Authentication
The IEEE 802.1x standard defines a client-server-based access control and authentication protocol that
prevents unauthorized clients from connecting to a LAN through publicly accessible ports unless they
are properly authenticated. The authentication server authenticates each client connected to a switch port
before making available any services offered by the switch or the LAN.
Until the client is authenticated, IEEE 802.1x access control allows only Extensible Authentication
Protocol over LAN (EAPOL), Cisco Discovery Protocol (CDP), and Spanning Tree Protocol (STP)
traffic through the port to which the client is connected. After authentication is successful, normal traffic
can pass through the port.
These sections describe IEEE 802.1x port-based authentication:
•
Device Roles, page 10-2
•
Authentication Process, page 10-3
•
Authentication Initiation and Message Exchange, page 10-5
•
Ports in Authorized and Unauthorized States, page 10-7
•
IEEE 802.1x Authentication and Switch Stacks, page 10-8
•
IEEE 802.1x Host Mode, page 10-8
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Understanding IEEE 802.1x Port-Based Authentication
•
IEEE 802.1x Accounting, page 10-9
•
IEEE 802.1x Accounting Attribute-Value Pairs, page 10-9
•
Using IEEE 802.1x Authentication with VLAN Assignment, page 10-10
•
Using IEEE 802.1x Authentication with Per-User ACLs, page 10-11
•
Using IEEE 802.1x Authentication with Guest VLAN, page 10-13
•
Using IEEE 802.1x Authentication with Restricted VLAN, page 10-14
•
Using IEEE 802.1x Authentication with Inaccessible Authentication Bypass, page 10-15
•
Using IEEE 802.1x Authentication with Voice VLAN Ports, page 10-16
•
Using IEEE 802.1x Authentication with Port Security, page 10-17
•
Using IEEE 802.1x Authentication with Wake-on-LAN, page 10-18
•
Using IEEE 802.1x Authentication with MAC Authentication Bypass, page 10-18
•
Network Admission Control Layer 2 IEEE 802.1x Validation, page 10-20
Device Roles
With IEEE 802.1x port-based authentication, the devices in the network have specific roles as shown in
Figure 10-1.
Figure 10-1
IEEE 802.1x Device Roles
Authentication
server
(RADIUS)
101229
Workstations
(clients)
•
Client—the device (workstation) that requests access to the LAN and switch services and responds
to requests from the switch. The workstation must be running IEEE 802.1x-compliant client
software such as that offered in the Microsoft Windows XP operating system. (The client is the
supplicant in the IEEE 802.1x standard.)
Note
•
To resolve Windows XP network connectivity and IEEE 802.1x authentication issues, read
the Microsoft Knowledge Base article at this URL:
http://support.microsoft.com/support/kb/articles/Q303/5/97.ASP
Authentication server—performs the actual authentication of the client. The authentication server
validates the identity of the client and notifies the switch whether or not the client is authorized to
access the LAN and switch services. Because the switch acts as the proxy, the authentication service
is transparent to the client. In this release, the RADIUS security system with Extensible
Authentication Protocol (EAP) extensions is the only supported authentication server. It is available
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Understanding IEEE 802.1x Port-Based Authentication
in Cisco Secure Access Control Server Version 3.0 or later. RADIUS operates in a client/server
model in which secure authentication information is exchanged between the RADIUS server and
one or more RADIUS clients.
•
Switch (edge switch or wireless access point)—controls the physical access to the network based on
the authentication status of the client. The switch acts as an intermediary (proxy) between the client
and the authentication server, requesting identity information from the client, verifying that
information with the authentication server, and relaying a response to the client. The switch includes
the RADIUS client, which is responsible for encapsulating and decapsulating the EAP frames and
interacting with the authentication server. (The switch is the authenticator in the IEEE 802.1x
standard.)
When the switch receives EAPOL frames and relays them to the authentication server, the Ethernet
header is stripped and the remaining EAP frame is re-encapsulated in the RADIUS format. The EAP
frames are not modified during encapsulation, and the authentication server must support EAP
within the native frame format. When the switch receives frames from the authentication server, the
server’s frame header is removed, leaving the EAP frame, which is then encapsulated for Ethernet
and sent to the client.
The devices that can act as intermediaries include the Catalyst 3750, Catalyst 3560, Catalyst 3550,
Catalyst 2970, Catalyst 2960, Catalyst 2955, Catalyst 2950, Catalyst 2940 switches, or a wireless
access point. These devices must be running software that supports the RADIUS client and IEEE
802.1x authentication.
Authentication Process
When IEEE 802.1x port-based authentication is enabled and the client supports IEEE 802.1x-compliant
client software, these events occur:
•
If the client identity is valid and the IEEE 802.1x authentication succeeds, the switch grants the
client access to the network.
•
If IEEE 802.1x authentication times out while waiting for an EAPOL message exchange and MAC
authentication bypass is enabled, the switch can use the client MAC address for authorization. If the
client MAC address is valid and the authorization succeeds, the switch grants the client access to the
network. If the client MAC address is invalid and the authorization fails, the switch assigns the client
to a guest VLAN that provides limited services if a guest VLAN is configured.
•
If the switch gets an invalid identity from an IEEE 802.1x-capable client and a restricted VLAN is
specified, the switch can assign the client to a restricted VLAN that provides limited services.
•
If the RADIUS authentication server is unavailable (down) and inaccessible authentication bypass
is enabled, the switch grants the client access to the network by putting the port in the
critical-authentication state in the RADIUS-configured or the user-specified access VLAN.
Note
Inaccessible authentication bypass is also referred to as critical authentication or the AAA fail
policy.
Figure 10-2 shows the authentication process.
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Understanding IEEE 802.1x Port-Based Authentication
Figure 10-2
Authentication Flowchart
Start
IEEE 802.1x authentication
process times out.
Is MAC authentication
bypass enabled? 1
Yes
Yes
Start IEEE 802.1x port-based
authentication.
Client
identity is
invalid
The switch gets an
EAPOL message,
and the EAPOL
message
exchange begins.
Client
identity is
valid
No
Use MAC authentication
bypass. 1
Client MAC
address
identity
is valid.
Client MAC
address
identity
is invalid.
Assign the port to
a restricted VLAN.
Assign the port to
a VLAN.
Assign the port to
a VLAN.
Assign the port to
a guest VLAN. 1
Done
Done
Done
Done
All authentication
servers are down.
141679
No
Is the client IEEE
802.1x capable?
All authentication
servers are down.
Use inaccessible
authentication bypass
(critical authentication)
to assign the critical
port to a VLAN.
Done
1 = This occurs if the switch does not detect EAPOL packets from the client.
The switch re-authenticates a client when one of these situations occurs:
•
Periodic re-authentication is enabled, and the re-authentication timer expires.
You can configure the re-authentication timer to use a switch-specific value or to be based on values
from the RADIUS server.
After IEEE 802.1x authentication using a RADIUS server is configured, the switch uses timers
based on the Session-Timeout RADIUS attribute (Attribute[27]) and the Termination-Action
RADIUS attribute (Attribute [29]).
The Session-Timeout RADIUS attribute (Attribute[27]) specifies the time after which
re-authentication occurs.
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Understanding IEEE 802.1x Port-Based Authentication
The Termination-Action RADIUS attribute (Attribute [29]) specifies the action to take during
re-authentication. The actions can be Initialize or ReAuthenticate. When the Initialize action is set
(the attribute value is DEFAULT), the IEEE 802.1x session ends, and connectivity is lost during
re-authentication. When the ReAuthenticate action is set (the attribute value is RADIUS-Request),
the session is not affected during re-authentication.
•
You manually re-authenticate the client by entering the dot1x re-authenticate interface
interface-id privileged EXEC command.
Authentication Initiation and Message Exchange
During IEEE 802.1x authentication, the switch or the client can initiate authentication. If you enable
authentication on a port by using the dot1x port-control auto interface configuration command, the
switch initiates authentication when the link state changes from down to up or periodically as long as
the port remains up and unauthenticated. The switch sends an EAP-request/identity frame to the client
to request its identity. Upon receipt of the frame, the client responds with an EAP-response/identity
frame.
However, if during bootup, the client does not receive an EAP-request/identity frame from the switch,
the client can initiate authentication by sending an EAPOL-start frame, which prompts the switch to
request the client’s identity.
Note
If IEEE 802.1x authentication is not enabled or supported on the network access device, any EAPOL
frames from the client are dropped. If the client does not receive an EAP-request/identity frame after
three attempts to start authentication, the client sends frames as if the port is in the authorized state. A
port in the authorized state effectively means that the client has been successfully authenticated. For
more information, see the “Ports in Authorized and Unauthorized States” section on page 10-7.
When the client supplies its identity, the switch begins its role as the intermediary, passing EAP frames
between the client and the authentication server until authentication succeeds or fails. If the
authentication succeeds, the switch port becomes authorized. If the authentication fails, authentication
can be retried, the port might be assigned to a VLAN that provides limited services, or network access
is not granted. For more information, see the “Ports in Authorized and Unauthorized States” section on
page 10-7.
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Understanding IEEE 802.1x Port-Based Authentication
The specific exchange of EAP frames depends on the authentication method being used. Figure 10-3
shows a message exchange initiated by the client using the One-Time-Password (OTP) authentication
method with a RADIUS server.
Figure 10-3
Message Exchange
Authentication
server
(RADIUS)
Client
EAPOL-Start
EAP-Request/Identity
EAP-Response/Identity
RADIUS Access-Request
EAP-Request/OTP
RADIUS Access-Challenge
EAP-Response/OTP
RADIUS Access-Request
EAP-Success
RADIUS Access-Accept
Port Authorized
Port Unauthorized
101228
EAPOL-Logoff
If IEEE 802.1x authentication times out while waiting for an EAPOL message exchange and MAC
authentication bypass is enabled, the switch can authorize the client when the switch detects an Ethernet
packet from the client. The switch uses the MAC address of the client as its identity and includes this
information in the RADIUS-access/request frame that is sent to the RADIUS server. After the server
sends the switch the RADIUS-access/accept frame (authorization is successful), the port becomes
authorized. If authorization fails and a guest VLAN is specified, the switch assigns the port to the guest
VLAN. If the switch detects an EAPOL packet while waiting for an Ethernet packet, the switch stops
the MAC authentication bypass process and initiates authentication using IEEE 802.1x authentication.
Figure 10-4 shows the message exchange during MAC authentication bypass.
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Understanding IEEE 802.1x Port-Based Authentication
Figure 10-4
Message Exchange During MAC Authentication Bypass
Client
Authentication
server
(RADIUS)
Switch
EAPOL Request/Identity
EAPOL Request/Identity
EAPOL Request/Identity
RADIUS Access/Request
RADIUS Access/Accept
141681
Ethernet packet
Ports in Authorized and Unauthorized States
During IEEE 802.1x authentication, depending on the switch port state, the switch can grant a client
access to the network. The port starts in the unauthorized state. While in this state, the port that is not
configured as a voice VLAN port disallows all ingress and egress traffic except for IEEE 802.1x
authentication, CDP, and STP packets. When a client is successfully authenticated, the port changes to
the authorized state, allowing all traffic for the client to flow normally. If the port is configured as a voice
VLAN port, the port allows VoIP traffic and IEEE 802.1x protocol packets before the client is
successfully authenticated.
If a client that does not support IEEE 802.1x authentication connects to an unauthorized IEEE 802.1x
port, the switch requests the client’s identity. In this situation, the client does not respond to the request,
the port remains in the unauthorized state, and the client is not granted access to the network.
In contrast, when an IEEE 802.1x-enabled client connects to a port that is not running the IEEE 802.1x
standard, the client initiates the authentication process by sending the EAPOL-start frame. When no
response is received, the client sends the request for a fixed number of times. Because no response is
received, the client begins sending frames as if the port is in the authorized state.
You control the port authorization state by using the dot1x port-control interface configuration
command and these keywords:
•
force-authorized—disables IEEE 802.1x authentication and causes the port to change to the
authorized state without any authentication exchange required. The port sends and receives normal
traffic without IEEE 802.1x-based authentication of the client. This is the default setting.
•
force-unauthorized—causes the port to remain in the unauthorized state, ignoring all attempts by
the client to authenticate. The switch cannot provide authentication services to the client through the
port.
•
auto—enables IEEE 802.1x authentication and causes the port to begin in the unauthorized state,
allowing only EAPOL frames to be sent and received through the port. The authentication process
begins when the link state of the port changes from down to up or when an EAPOL-start frame is
received. The switch requests the identity of the client and begins relaying authentication messages
between the client and the authentication server. Each client attempting to access the network is
uniquely identified by the switch by using the client MAC address.
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Understanding IEEE 802.1x Port-Based Authentication
If the client is successfully authenticated (receives an Accept frame from the authentication server), the
port state changes to authorized, and all frames from the authenticated client are allowed through the
port. If the authentication fails, the port remains in the unauthorized state, but authentication can be
retried. If the authentication server cannot be reached, the switch can resend the request. If no response
is received from the server after the specified number of attempts, authentication fails, and network
access is not granted.
When a client logs off, it sends an EAPOL-logoff message, causing the switch port to change to the
unauthorized state.
If the link state of a port changes from up to down, or if an EAPOL-logoff frame is received, the port
returns to the unauthorized state.
IEEE 802.1x Authentication and Switch Stacks
If a switch is added to or removed from a switch stack, IEEE 802.1x authentication is not affected as
long as the IP connectivity between the RADIUS server and the stack remains intact. This statement also
applies if the stack master is removed from the switch stack. Note that if the stack master fails, a stack
member becomes the new stack master by using the election process described in Chapter 5, “Managing
Switch Stacks,” and the IEEE 802.1x authentication process continues as usual.
If IP connectivity to the RADIUS server is interrupted because the switch that was connected to the
server is removed or fails, these events occur:
•
Ports that are already authenticated and that do not have periodic re-authentication enabled remain
in the authenticated state. Communication with the RADIUS server is not required.
•
Ports that are already authenticated and that have periodic re-authentication enabled (with the dot1x
re-authentication global configuration command) fail the authentication process when the
re-authentication occurs. Ports return to the unauthenticated state during the re-authentication
process. Communication with the RADIUS server is required.
For an ongoing authentication, the authentication fails immediately because there is no server
connectivity.
If the switch that failed comes up and rejoins the switch stack, the authentications might or might not
fail depending on the boot-up time and whether the connectivity to the RADIUS server is re-established
by the time the authentication is attempted.
To avoid loss of connectivity to the RADIUS server, you should ensure that there is a redundant
connection to it. For example, you can have a redundant connection to the stack master and another to a
stack member, and if the stack master fails, the switch stack still has connectivity to the RADIUS server.
IEEE 802.1x Host Mode
You can configure an IEEE 802.1x port for single-host or for multiple-hosts mode. In single-host mode
(see Figure 10-1 on page 10-2), only one client can be connected to the IEEE 802.1x-enabled switch
port. The switch detects the client by sending an EAPOL frame when the port link state changes to the
up state. If a client leaves or is replaced with another client, the switch changes the port link state to
down, and the port returns to the unauthorized state.
In multiple-hosts mode, you can attach multiple hosts to a single IEEE 802.1x-enabled port. Figure 10-5
on page 10-9 shows IEEE 802.1x port-based authentication in a wireless LAN. In this mode, only one
of the attached clients must be authorized for all clients to be granted network access. If the port becomes
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Understanding IEEE 802.1x Port-Based Authentication
unauthorized (re-authentication fails or an EAPOL-logoff message is received), the switch denies
network access to all of the attached clients. In this topology, the wireless access point is responsible for
authenticating the clients attached to it, and it also acts as a client to the switch.
With the multiple-hosts mode enabled, you can use IEEE 802.1x authentication to authenticate the port
and port security to manage network access for all MAC addresses, including that of the client.
Figure 10-5
Multiple Host Mode Example
Authentication
server
(RADIUS)
Access point
101227
Wireless clients
IEEE 802.1x Accounting
The IEEE 802.1x standard defines how users are authorized and authenticated for network access but
does not keep track of network usage. IEEE 802.1x accounting is disabled by default. You can enable
IEEE 802.1x accounting to monitor this activity on IEEE 802.1x-enabled ports:
•
User successfully authenticates.
•
User logs off.
•
Link-down occurs.
•
Re-authentication successfully occurs.
•
Re-authentication fails.
The switch does not log IEEE 802.1x accounting information. Instead, it sends this information to the
RADIUS server, which must be configured to log accounting messages.
IEEE 802.1x Accounting Attribute-Value Pairs
The information sent to the RADIUS server is represented in the form of Attribute-Value (AV) pairs.
These AV pairs provide data for different applications. (For example, a billing application might require
information that is in the Acct-Input-Octets or the Acct-Output-Octets attributes of a RADIUS packet.)
AV pairs are automatically sent by a switch that is configured for IEEE 802.1x accounting. Three types
of RADIUS accounting packets are sent by a switch:
•
START–sent when a new user session starts
•
INTERIM–sent during an existing session for updates
•
STOP–sent when a session terminates
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Table 10-1 lists the AV pairs and when they are sent are sent by the switch:
Table 10-1
Accounting AV Pairs
Attribute Number
AV Pair Name
START
INTERIM
STOP
Attribute[1]
User-Name
Always
Always
Always
Attribute[4]
NAS-IP-Address
Always
Always
Always
Attribute[5]
NAS-Port
Always
Always
Always
1
Sometimes1
Attribute[8]
Framed-IP-Address
Never
Sometimes
Attribute[25]
Class
Always
Always
Always
Attribute[30]
Called-Station-ID
Always
Always
Always
Attribute[31]
Calling-Station-ID
Always
Always
Always
Attribute[40]
Acct-Status-Type
Always
Always
Always
Attribute[41]
Acct-Delay-Time
Always
Always
Always
Attribute[42]
Acct-Input-Octets
Never
Never
Always
Attribute[43]
Acct-Output-Octets
Never
Never
Always
Attribute[44]
Acct-Session-ID
Always
Always
Always
Attribute[45]
Acct-Authentic
Always
Always
Always
Attribute[46]
Acct-Session-Time
Never
Never
Always
Attribute[49]
Acct-Terminate-Cause
Never
Never
Always
Attribute[61]
NAS-Port-Type
Always
Always
Always
1. The Framed-IP-Address AV pair is sent only if a valid Dynamic Host Control Protocol (DHCP) binding
exists for the host in the DHCP snooping bindings table.
You can view the AV pairs that are being sent by the switch by entering the debug radius accounting
privileged EXEC command. For more information about this command, see the Cisco IOS Debug
Command Reference, Release 12.2 at this URL:
http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_command_reference_book09186a008
00872ce.html
For more information about AV pairs, see RFC 3580, “IEEE 802.1X Remote Authentication Dial In User
Service (RADIUS) Usage Guidelines.”
Using IEEE 802.1x Authentication with VLAN Assignment
Before Cisco IOS Release 12.1(14)EA1, when an IEEE 802.1x port was authenticated, it was authorized
to be in the access VLAN configured on the port even if the RADIUS server returned an authorized
VLAN from its database. Recall that an access VLAN is a VLAN assigned to an access port. All packets
sent from or received on this port belong to this VLAN.
However, with Cisco IOS Release 12.1(14)EA1 and later releases, the switch supports IEEE 802.1x
authentication with VLAN assignment. After successful IEEE 802.1x authentication of a port, the
RADIUS server sends the VLAN assignment to configure the switch port. The RADIUS server database
maintains the username-to-VLAN mappings, assigning the VLAN based on the username of the client
connected to the switch port. You can use this feature to limit network access for certain users.
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When configured on the switch and the RADIUS server, IEEE 802.1x authentication with VLAN
assignment has these characteristics:
•
If no VLAN is supplied by the RADIUS server or if IEEE 802.1x authentication is disabled, the port
is configured in its access VLAN after successful authentication.
•
If IEEE 802.1x authentication is enabled but the VLAN information from the RADIUS server is not
valid, the port returns to the unauthorized state and remains in the configured access VLAN. This
prevents ports from appearing unexpectedly in an inappropriate VLAN because of a configuration
error.
Configuration errors could include specifying a VLAN for a routed port, a malformed VLAN ID, a
nonexistent or internal (routed port) VLAN ID, or an attempted assignment to a voice VLAN ID.
•
If IEEE 802.1x authentication is enabled and all information from the RADIUS server is valid, the
port is placed in the specified VLAN after authentication.
•
If the multiple-hosts mode is enabled on an IEEE 802.1x port, all hosts are placed in the same VLAN
(specified by the RADIUS server) as the first authenticated host.
•
If IEEE 802.1x authentication and port security are enabled on a port, the port is placed in the
RADIUS server-assigned VLAN.
•
If IEEE 802.1x authentication is disabled on the port, it is returned to the configured access VLAN.
When the port is in the force authorized, force unauthorized, unauthorized, or shutdown state, it is put
into the configured access VLAN.
If an IEEE 802.1x port is authenticated and put in the RADIUS server-assigned VLAN, any change to
the port access VLAN configuration does not take effect.
The IEEE 802.1x authentication with VLAN assignment feature is not supported on trunk ports, dynamic
ports, or with dynamic-access port assignment through a VLAN Membership Policy Server (VMPS).
To configure VLAN assignment you need to perform these tasks:
•
Enable AAA authorization by using the network keyword to allow interface configuration from the
RADIUS server.
•
Enable IEEE 802.1x authentication. (The VLAN assignment feature is automatically enabled when
you configure IEEE 802.1x authentication on an access port).
•
Assign vendor-specific tunnel attributes in the RADIUS server. The RADIUS server must return
these attributes to the switch:
– [64] Tunnel-Type = VLAN
– [65] Tunnel-Medium-Type = 802
– [81] Tunnel-Private-Group-ID = VLAN name or VLAN ID
Attribute [64] must contain the value VLAN (type 13). Attribute [65] must contain the value 802
(type 6). Attribute [81] specifies the VLAN name or VLAN ID assigned to the
IEEE 802.1x-authenticated user.
For examples of tunnel attributes, see the “Configuring the Switch to Use Vendor-Specific RADIUS
Attributes” section on page 9-29.
Using IEEE 802.1x Authentication with Per-User ACLs
You can enable per-user access control lists (ACLs) to provide different levels of network access and
service to an IEEE 802.1x-authenticated user. When the RADIUS server authenticates a user connected
to an IEEE 802.1x port, it retrieves the ACL attributes based on the user identity and sends them to the
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Understanding IEEE 802.1x Port-Based Authentication
switch. The switch applies the attributes to the IEEE 802.1x port for the duration of the user session. The
switch removes the per-user ACL configuration when the session is over, if authentication fails, or if a
link-down condition occurs. The switch does not save RADIUS-specified ACLs in the running
configuration. When the port is unauthorized, the switch removes the ACL from the port.
You can configure router ACLs and input port ACLs on the same switch. However, a port ACL takes
precedence over a router ACL. If you apply input port ACL to an interface that belongs to a VLAN, the
port ACL takes precedence over an input router ACL applied to the VLAN interface. Incoming packets
received on the port to which a port ACL is applied are filtered by the port ACL. Incoming routed packets
received on other ports are filtered by the router ACL. Outgoing routed packets are filtered by the router
ACL. To avoid configuration conflicts, you should carefully plan the user profiles stored on the RADIUS
server.
RADIUS supports per-user attributes, including vendor-specific attributes. These vendor-specific
attributes (VSAs) are in octet-string format and are passed to the switch during the authentication
process. The VSAs used for per-user ACLs are inacl#<n> for the ingress direction and outacl#<n> for
the egress direction. MAC ACLs are supported only in the ingress direction. The switch supports VSAs
only in the ingress direction. It does not support port ACLs in the egress direction on Layer 2 ports. For
more information, see Chapter 32, “Configuring Network Security with ACLs.”
Use only the extended ACL syntax style to define the per-user configuration stored on the RADIUS
server. When the definitions are passed from the RADIUS server, they are created by using the extended
naming convention. However, if you use the Filter-Id attribute, it can point to a standard ACL.
You can use the Filter-Id attribute to specify an inbound or outbound ACL that is already configured on
the switch. The attribute contains the ACL number followed by .in for ingress filtering or .out for egress
filtering. If the RADIUS server does not allow the .in or .out syntax, the access list is applied to the
outbound ACL by default. Because of limited support of Cisco IOS access lists on the switch, the
Filter-Id attribute is supported only for IP ACLs numbered 1 to 199 and 1300 to 2699 (IP standard and
IP extended ACLs).
Only one IEEE 802.1x-authenticated user is supported on a port. If the multiple-hosts mode is enabled
on the port, the per-user ACL attribute is disabled for the associated port.
The maximum size of the per-user ACL is 4000 ASCII characters but is limited by the maximum size of
RADIUS- server per-user ACLs.
For examples of vendor-specific attributes, see the “Configuring the Switch to Use Vendor-Specific
RADIUS Attributes” section on page 9-29. For more information about configuring ACLs, see
Chapter 32, “Configuring Network Security with ACLs.”
To configure per-user ACLs, you need to perform these tasks:
•
Enable AAA authentication.
•
Enable AAA authorization by using the network keyword to allow interface configuration from the
RADIUS server.
•
Enable IEEE 802.1x authentication.
•
Configure the user profile and VSAs on the RADIUS server.
•
Configure the IEEE 802.1x port for single-host mode.
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Configuring IEEE 802.1x Port-Based Authentication
Understanding IEEE 802.1x Port-Based Authentication
Using IEEE 802.1x Authentication with Guest VLAN
You can configure a guest VLAN for each IEEE 802.1x port on the switch to provide limited services to
clients, such as downloading the IEEE 802.1x client. These clients might be upgrading their system for
IEEE 802.1x authentication, and some hosts, such as Windows 98 systems, might not be
IEEE 802.1x-capable.
When you enable a guest VLAN on an IEEE 802.1x port, the switch assigns clients to a guest VLAN
when the switch does not receive a response to its EAP request/identity frame or when EAPOL packets
are not sent by the client.
With Cisco IOS Release 12.2(25)SE and later, the switch maintains the EAPOL packet history. If an
EAPOL packet is detected on the interface during the lifetime of the link, the switch determines that the
device connected to that interface is an IEEE 802.1x-capable supplicant, and the interface does not
change to the guest VLAN state. EAPOL history is cleared if the interface link status goes down. If no
EAPOL packet is detected on the interface, the interface changes to the guest VLAN state.
Before Cisco IOS Release 12.2(25)SE, the switch did not maintain the EAPOL packet history and
allowed clients that failed authentication access to the guest VLAN, regardless of whether EAPOL
packets had been detected on the interface. You can enable this optional behavior by using the dot1x
guest-vlan supplicant global configuration command. However, in Cisco IOS Release 12.2(25)SEE, the
dot1x guest-vlan supplicant global configuration command is no longer supported. Use a restricted
VLAN to allow clients that failed authentication access to the network by entering the dot1x auth-fail
vlan vlan-id interface configuration command.
In Cisco IOS Release 12.2(25)SEE and later, if devices send EAPOL packets to the switch during the
lifetime of the link, the switch no longer allows clients that fail authentication access to the guest VLAN.
Note
If an EAPOL packet is detected after the interface has changed to the guest VLAN, the interface reverts
to an unauthorized state, and 802.1x authentication restarts.
Any number of IEEE 802.1x-incapable clients are allowed access when the switch port is moved to the
guest VLAN. If an IEEE 802.1x-capable client joins the same port on which the guest VLAN is
configured, the port is put into the unauthorized state in the user-configured access VLAN, and
authentication is restarted.
Guest VLANs are supported on IEEE 802.1x ports in single-host or multiple-hosts mode.
You can configure any active VLAN except an RSPAN VLAN, a private VLAN, or a voice VLAN as an
IEEE 802.1x guest VLAN. The guest VLAN feature is not supported on internal VLANs (routed ports)
or trunk ports; it is supported only on access ports.
The switch supports MAC authentication bypass in Cisco IOS Release 12.2(25)SEE and later. When
MAC authentication bypass is enabled on an IEEE 802.1x port, the switch can authorize clients based
on the client MAC address when IEEE 802.1x authentication times out while waiting for an EAPOL
message exchange. After detecting a client on an IEEE 802.1x port, the switch waits for an Ethernet
packet from the client. The switch sends the authentication server a RADIUS-access/request frame with
a username and password based on the MAC address. If authorization succeeds, the switch grants the
client access to the network. If authorization fails, the switch assigns the port to the guest VLAN if one
is specified. For more information, see the“Using IEEE 802.1x Authentication with MAC
Authentication Bypass” section on page 10-18.
For more information, see the “Configuring a Guest VLAN” section on page 10-33.
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Configuring IEEE 802.1x Port-Based Authentication
Understanding IEEE 802.1x Port-Based Authentication
Using IEEE 802.1x Authentication with Restricted VLAN
You can configure a restricted VLAN (also referred to as an authentication failed VLAN) for each
IEEE 802.1x port on a switch stack or a switch to provide limited services to clients that cannot access
the guest VLAN. These clients are IEEE 802.1x-compliant and cannot access another VLAN because
they fail the authentication process. A restricted VLAN allows users without valid credentials in an
authentication server (typically, visitors to an enterprise) to access a limited set of services. The
administrator can control the services available to the restricted VLAN.
Note
You can configure a VLAN to be both the guest VLAN and the restricted VLAN if you want to provide
the same services to both types of users.
Without this feature, the client attempts and fails authentication indefinitely, and the switch port remains
in the spanning-tree blocking state. With this feature, you can configure the switch port to be in the
restricted VLAN after a specified number of authentication attempts (the default value is 3 attempts).
The authenticator counts the failed authentication attempts for the client. When this count exceeds the
configured maximum number of authentication attempts, the port moves to the restricted VLAN. The
failed attempt count increments when the RADIUS server replies with either an EAP failure or an empty
response without an EAP packet. When the port moves into the restricted VLAN, the failed attempt
counter resets.
Users who fail authentication remain in the restricted VLAN until the next re-authentication attempt. A
port in the restricted VLAN tries to re-authenticate at configured intervals (the default is 60 seconds). If
re-authentication fails, the port remains in the restricted VLAN. If re-authentication is successful, the
port moves either to the configured VLAN or to a VLAN sent by the RADIUS server. You can disable
re-authentication. If you do this, the only way to restart the authentication process is for the port to
receive a link down or EAP logoff event. We recommend that you keep re-authentication enabled if a
client might connect through a hub. When a client disconnects from the hub, the port might not receive
the link down or EAP logoff event.
After a port moves to the restricted VLAN, a simulated EAP success message is sent to the client. This
prevents clients from indefinitely attempting authentication. Some clients (for example, devices running
Windows XP) cannot implement DHCP without EAP success.
Restricted VLANs are supported only on IEEE 802.1x ports in single-host mode and on Layer 2 ports.
You can configure any active VLAN except an RSPAN VLAN, a primary private VLAN, or a voice
VLAN as an IEEE 802.1x restricted VLAN. The restricted VLAN feature is not supported on internal
VLANs (routed ports) or trunk ports; it is supported only on access ports.
This feature works with port security. As soon as the port is authorized, a MAC address is provided to
port security. If port security does not permit the MAC address or if the maximum secure address count
is reached, the port becomes unauthorized and error disabled.
Other port security features such as dynamic ARP Inspection, DHCP snooping, and IP source guard can
be configured independently on a restricted VLAN.
For more information, see the “Configuring a Restricted VLAN” section on page 10-34.
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Configuring IEEE 802.1x Port-Based Authentication
Understanding IEEE 802.1x Port-Based Authentication
Using IEEE 802.1x Authentication with Inaccessible Authentication Bypass
In Cisco IOS Release 12.2(25)SEDand later, when the switch cannot reach the configured RADIUS
servers and hosts cannot be authenticated, you can configure the switch to allow network access to the
hosts connected to critical ports. A critical port is enabled for the inaccessible authentication bypass
feature, also referred to as critical authentication or the AAA fail policy.
When this feature is enabled, the switch checks the status of the configured RADIUS servers whenever
the switch tries to authenticate a host connected to a critical port. If a server is available, the switch can
authenticate the host. However, if all the RADIUS servers are unavailable, the switch grants network
access to the host and puts the port in the critical-authentication state, which is a special case of the
authentication state.
The behavior of the inaccessible authentication bypass feature depends on the authorization state of the
port:
•
If the port is unauthorized when a host connected to a critical port tries to authenticate and all servers
are unavailable, the switch puts the port in the critical-authentication state in the
RADIUS-configured or user-specified access VLAN.
•
If the port is already authorized and re-authentication occurs, the switch puts the critical port in the
critical-authentication state in the current VLAN, which might be the one previously assigned by
the RADIUS server.
•
If the RADIUS server becomes unavailable during an authentication exchange, the current
exchanges times out, and the switch puts the critical port in the critical-authentication state during
the next authentication attempt.
When a RADIUS server that can authenticate the host is available, all critical ports in the
critical-authentication state are automatically re-authenticated.
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Configuring IEEE 802.1x Port-Based Authentication
Understanding IEEE 802.1x Port-Based Authentication
Inaccessible authentication bypass interacts with these features:
•
Guest VLAN—Inaccessible authentication bypass is compatible with guest VLAN. When a guest
VLAN is enabled on IEEE 8021.x port, the features interact as follows:
– If at least one RADIUS server is available, the switch assigns a client to a guest VLAN when
the switch does not receive a response to its EAP request/identity frame or when EAPOL
packets are not sent by the client.
– If all the RADIUS servers are not available and the client is connected to a critical port, the
switch authenticates the client and puts the critical port in the critical-authentication state in the
RADIUS-configured or user-specified access VLAN.
– If all the RADIUS servers are not available and the client is not connected to a critical port, the
switch might not assign clients to the guest VLAN if one is configured.
– If all the RADIUS servers are not available and if a client is connected to a critical port and was
previously assigned to a guest VLAN, the switch keeps the port in the guest VLAN.
•
Restricted VLAN—If the port is already authorized in a restricted VLAN and the RADIUS servers
are unavailable, the switch puts the critical port in the critical-authentication state in the restricted
VLAN.
•
IEEE 802.1x accounting—Accounting is not affected if the RADIUS servers are unavailable.
•
Private VLAN—You can configure inaccessible authentication bypass on the private VLAN host
port. The access VLAN must be a secondary private VLAN.
•
Voice VLAN—Inaccessible authentication bypass is compatible with voice VLAN, but the
RADIUS-configured or user-specified access VLAN and the voice VLAN must be different.
•
Remote Switched Port Analyzer (RSPAN)—Do not configure an RSPAN VLAN as the
RADIUS-configured or user-specified access VLAN for inaccessible authentication bypass.
In a switch stack, the stack master checks the status of the RADIUS servers by sending keepalive
packets. When the status of a RADIUS server changes, the stack master sends the information to the
stack members. The stack members can then check the status of RADIUS servers when re-authenticating
critical ports.
If the new stack master is elected, the link between the switch stack and RADIUS server might change,
and the new stack immediately sends keepalive packets to update the status of the RADIUS servers. If
the server status changes from dead to alive, the switch re-authenticates all switch ports in the
critical-authentication state.
When a member is added to the stack, the stack master sends the member the server status.
Using IEEE 802.1x Authentication with Voice VLAN Ports
A voice VLAN port is a special access port associated with two VLAN identifiers:
•
VVID to carry voice traffic to and from the IP phone. The VVID is used to configure the IP phone
connected to the port.
•
PVID to carry the data traffic to and from the workstation connected to the switch through the IP
phone. The PVID is the native VLAN of the port.
Before Cisco IOS Release 12.1(14)EA1, a switch in single-host mode accepted traffic from a single host,
and voice traffic was not allowed. In multiple-hosts mode, the switch did not accept voice traffic until
the client was authenticated on the primary VLAN, thus making the IP phone inoperable until the user
logged in.
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Configuring IEEE 802.1x Port-Based Authentication
Understanding IEEE 802.1x Port-Based Authentication
With Cisco IOS Release 12.1(14)EA1 and later, the IP phone uses the VVID for its voice traffic,
regardless of the authorization state of the port. This allows the phone to work independently of
IEEE 802.1x authentication.
In single-host mode, only the IP phone is allowed on the voice VLAN. In multiple-hosts mode,
additional clients can send traffic on the voice VLAN after a supplicant is authenticated on the PVID.
When multiple-hosts mode is enabled, the supplicant authentication affects both the PVID and the
VVID.
A voice VLAN port becomes active when there is a link, and the device MAC address appears after the
first CDP message from the IP phone. Cisco IP phones do not relay CDP messages from other devices.
As a result, if several IP phones are connected in series, the switch recognizes only the one directly
connected to it. When IEEE 802.1x authentication is enabled on a voice VLAN port, the switch drops
packets from unrecognized IP phones more than one hop away.
When IEEE 802.1x authentication is enabled on a port, you cannot configure a port VLAN that is equal
to a voice VLAN.
Note
If you enable IEEE 802.1x authentication on an access port on which a voice VLAN is configured and
to which a Cisco IP Phone is connected, the Cisco IP phone loses connectivity to the switch for up to 30
seconds.
For more information about voice VLANs, see Chapter 15, “Configuring Voice VLAN.”
Using IEEE 802.1x Authentication with Port Security
You can configure an IEEE 802.1x port with port security in either single-host or multiple-hosts mode.
(You also must configure port security on the port by using the switchport port-security interface
configuration command.) When you enable port security and IEEE 802.1x authentication on a port, IEEE
802.1x authentication authenticates the port, and port security manages network access for all MAC
addresses, including that of the client. You can then limit the number or group of clients that can access
the network through an IEEE 802.1x port.
These are some examples of the interaction between IEEE 802.1x authentication and port security on the
switch:
•
When a client is authenticated, and the port security table is not full, the client MAC address is added
to the port security list of secure hosts. The port then proceeds to come up normally.
When a client is authenticated and manually configured for port security, it is guaranteed an entry
in the secure host table (unless port security static aging has been enabled).
A security violation occurs if the client is authenticated, but the port security table is full. This can
happen if the maximum number of secure hosts has been statically configured or if the client ages
out of the secure host table. If the client address is aged, its place in the secure host table can be
taken by another host.
If the security violation is caused by the first authenticated host, the port becomes error-disabled and
immediately shuts down.
The port security violation modes determine the action for security violations. For more
information, see the “Security Violations” section on page 25-9.
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Configuring IEEE 802.1x Port-Based Authentication
Understanding IEEE 802.1x Port-Based Authentication
•
When you manually remove an IEEE 802.1x client address from the port security table by using the
no switchport port-security mac-address mac-address interface configuration command, you
should re-authenticate the IEEE 802.1x client by using the dot1x re-authenticate interface
interface-id privileged EXEC command.
•
When an IEEE 802.1x client logs off, the port changes to an unauthenticated state, and all dynamic
entries in the secure host table are cleared, including the entry for the client. Normal authentication
then takes place.
•
If the port is administratively shut down, the port becomes unauthenticated, and all dynamic entries
are removed from the secure host table.
•
Port security and a voice VLAN can be configured simultaneously on an IEEE 802.1x port that is in
either single-host or multiple-hosts mode. Port security applies to both the voice VLAN identifier
(VVID) and the port VLAN identifier (PVID).
For more information about enabling port security on your switch, see the “Configuring Port Security”
section on page 25-7.
Using IEEE 802.1x Authentication with Wake-on-LAN
The IEEE 802.1x authentication with wake-on-LAN (WoL) feature allows dormant PCs to be powered
when the switch receives a specific Ethernet frame, known as the magic packet. You can use this feature
in environments where administrators need to connect to systems that have been powered down. This
feature is also known as the unidirectional controlled port in the IEEE 802.1x standard.
When a host that uses WoL is attached through an IEEE 802.1x port and the host powers off, the
IEEE 802.1x port becomes unauthorized. The port can only receive and send EAPOL packets, and WoL
magic packets cannot reach the host. When the PC is powered off, it is not authorized, and the switch
port is not opened.
When the switch uses IEEE 802.1x authentication with WoL, the switch forwards traffic to unauthorized
IEEE 802.1x ports, including magic packets. While the port is unauthorized, the switch continues to
block ingress traffic other than EAPOL packets. The host can receive packets but cannot send packets to
other devices in the network.
Note
If PortFast is not enabled on the port, the port is forced to the bidirectional state.
When you configure a port as unidirectional by using the dot1x control-direction in interface
configuration command, the port changes to the spanning-tree forwarding state. The port can send
packets to the host but cannot receive packets from the host.
When you configure a port as bidirectional by using the dot1x control-direction both interface
configuration command, the port is access-controlled in both directions. The port does not receive
packets from or send packets to the host.
Using IEEE 802.1x Authentication with MAC Authentication Bypass
You can configure the switch to authorize clients based on the client MAC address (see Figure 10-2 on
page 10-4) by using the MAC authentication bypass feature. For example, you can enable this feature on
IEEE 802.1x ports connected to devices such as printers.
If IEEE 802.1x authentication times out while waiting for an EAPOL response from the client, the switch
tries to authorize the client by using MAC authentication bypass.
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Configuring IEEE 802.1x Port-Based Authentication
Understanding IEEE 802.1x Port-Based Authentication
When the MAC authentication bypass feature is enabled on an IEEE 802.1x port, the switch uses the
MAC address as the client identity. The authentication server has a database of client MAC addresses
that are allowed network access. After detecting a client on an IEEE 802.1x port, the switch waits for an
Ethernet packet from the client. The switch sends the authentication server a RADIUS-access/request
frame with a username and password based on the MAC address. If authorization succeeds, the switch
grants the client access to the network. If authorization fails, the switch assigns the port to the guest
VLAN if one is configured.
If an EAPOL packet is detected on the interface during the lifetime of the link, the switch determines
that the device connected to that interface is an IEEE 802.1x-capable supplicant and uses IEEE 802.1x
authentication (not MAC authentication bypass) to authorize the interface. EAPOL history is cleared if
the interface link status goes down.
If the switch already authorized a port by using MAC authentication bypass and detects an IEEE 802.1x
supplicant, the switch does not unauthorize the client connected to the port. When re-authentication
occurs, the switch uses IEEE 802.1x authentication as the preferred re-authentication process if the
previous session ended because the Termination-Action RADIUS attribute value is DEFAULT.
Clients that were authorized with MAC authentication bypass can be re-authenticated. The
re-authentication process is the same as that for clients that were authenticated with IEEE 802.1x.
During re-authentication, the port remains in the previously assigned VLAN. If re-authentication is
successful, the switch keeps the port in the same VLAN. If re-authentication fails, the switch assigns the
port to the guest VLAN, if one is configured.
If re-authentication is based on the Session-Timeout RADIUS attribute (Attribute[27]) and the
Termination-Action RADIUS attribute (Attribute [29]) and if the Termination-Action RADIUS attribute
(Attribute [29]) action is Initialize, (the attribute value is DEFAULT), the MAC authentication bypass
session ends, and connectivity is lost during re-authentication. If MAC authentication bypass is enabled
and the IEEE 802.1x authentication times out, the switch uses the MAC authentication bypass feature to
initiate re-authorization. For more information about these AV pairs, see RFC 3580, “IEEE 802.1X
Remote Authentication Dial In User Service (RADIUS) Usage Guidelines.”
MAC authentication bypass interacts with the features:
•
IEEE 802.1x authentication—You can enable MAC authentication bypass only if IEEE 802.1x
authentication is enabled on the port.
•
Guest VLAN—If a client has an invalid MAC address identity, the switch assigns the client to a
guest VLAN if one is configured.
•
Restricted VLAN—This feature is not supported when the client connected to an IEEE 802.lx port
is authenticated with MAC authentication bypass.
•
Port security—See the “Using IEEE 802.1x Authentication with Port Security” section on
page 10-17.
•
Voice VLAN—See the “Using IEEE 802.1x Authentication with Voice VLAN Ports” section on
page 10-16.
•
VLAN Membership Policy Server (VMPS)—IEEE802.1x and VMPS are mutually exclusive.
•
Private VLAN—You can assign a client to a private VLAN.
•
Network admission control (NAC) Layer 2 IP validation—This feature takes effect after an
IEEE 802.1x port is authenticated with MAC authentication bypass, including hosts in the exception
list.
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Configuring IEEE 802.1x Port-Based Authentication
Configuring IEEE 802.1x Authentication
Network Admission Control Layer 2 IEEE 802.1x Validation
In Cisco IOS Release 12.2(25)SED and later, the switch supports the Network Admission Control (NAC)
Layer 2 IEEE 802.1x validation, which checks the antivirus condition or posture of endpoint systems or
clients before granting the devices network access. With NAC Layer 2 IEEE 802.1x validation, you can
do these tasks:
•
Download the Session-Timeout RADIUS attribute (Attribute[27]) and the Termination-Action
RADIUS attribute (Attribute[29]) from the authentication server.
•
Set the number of seconds between re-authentication attempts as the value of the Session-Timeout
RADIUS attribute (Attribute[27]) and get an access policy against the client from the RADIUS
server.
•
Set the action to be taken when the switch tries to re-authenticate the client by using the
Termination-Action RADIUS attribute (Attribute[29]). If the value is the DEFAULT or is not set, the
session ends. If the value is RADIUS-Request, the re-authentication process starts.
•
View the NAC posture token, which shows the posture of the client, by using the show dot1x
privileged EXEC command.
•
Configure secondary private VLANs as guest VLANs.
Configuring NAC Layer 2 IEEE 802.1x validation is similar to configuring IEEE 802.1x port-based
authentication except that you must configure a posture token on the RADIUS server. For information
about configuring NAC Layer 2 IEEE 802.1x validation, see the “Configuring NAC Layer 2 IEEE 802.1x
Validation” section on page 10-39 and the “Configuring Periodic Re-Authentication” section on
page 10-28.
For more information about NAC, see the Network Admission Control Software Configuration Guide.
Configuring IEEE 802.1x Authentication
These sections contain this configuration information:
•
Default IEEE 802.1x Authentication Configuration, page 10-21
•
IEEE 802.1x Authentication Configuration Guidelines, page 10-22
•
Upgrading from a Previous Software Release, page 10-24
•
Configuring IEEE 802.1x Authentication, page 10-25 (required)
•
Configuring the Switch-to-RADIUS-Server Communication, page 10-26 (required)
•
Configuring the Host Mode, page 10-28 (optional)
•
Configuring Periodic Re-Authentication, page 10-28 (optional)
•
Manually Re-Authenticating a Client Connected to a Port, page 10-29 (optional)
•
Changing the Quiet Period, page 10-29 (optional)
•
Changing the Switch-to-Client Retransmission Time, page 10-30 (optional)
•
Setting the Switch-to-Client Frame-Retransmission Number, page 10-31 (optional)
•
Setting the Re-Authentication Number, page 10-31 (optional)
•
Configuring IEEE 802.1x Accounting, page 10-32 (optional)
•
Configuring a Guest VLAN, page 10-33 (optional)
•
Configuring a Restricted VLAN, page 10-34 (optional)
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Configuring IEEE 802.1x Authentication
•
Configuring the Inaccessible Authentication Bypass Feature, page 10-36 (optional)
•
Configuring IEEE 802.1x Authentication with WoL, page 10-38 (optional)
•
Configuring MAC Authentication Bypass, page 10-38 (optional)
•
“Configuring NAC Layer 2 IEEE 802.1x Validation” section on page 10-39 (optional)
•
Disabling IEEE 802.1x Authentication on the Port, page 10-40 (optional)
•
Resetting the IEEE 802.1x Authentication Configuration to the Default Values, page 10-40
(optional)
Default IEEE 802.1x Authentication Configuration
Table 10-2 shows the default IEEE 802.1x authentication configuration.
Table 10-2
Default IEEE 802.1x Authentication Configuration
Feature
Default Setting
Switch IEEE 802.1x enable state
Disabled.
Per-port IEEE 802.1x enable state
Disabled (force-authorized).
The port sends and receives normal traffic without IEEE
802.1x-based authentication of the client.
AAA
Disabled.
RADIUS server
•
IP address
•
None specified.
•
UDP authentication port
•
1812.
•
Key
•
None specified.
Host mode
Single-host mode.
Control direction
Bidirectional control.
Periodic re-authentication
Disabled.
Number of seconds between
re-authentication attempts
3600 seconds.
Re-authentication number
2 times (number of times that the switch restarts the
authentication process before the port changes to the
unauthorized state).
Quiet period
60 seconds (number of seconds that the switch remains in
the quiet state following a failed authentication exchange
with the client).
Retransmission time
30 seconds (number of seconds that the switch should
wait for a response to an EAP request/identity frame
from the client before resending the request).
Maximum retransmission number
2 times (number of times that the switch will send an
EAP-request/identity frame before restarting the
authentication process).
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Configuring IEEE 802.1x Authentication
Table 10-2
Default IEEE 802.1x Authentication Configuration (continued)
Feature
Default Setting
Client timeout period
30 seconds (when relaying a request from the
authentication server to the client, the amount of time the
switch waits for a response before resending the request
to the client.)
Authentication server timeout period
30 seconds (when relaying a response from the client to
the authentication server, the amount of time the switch
waits for a reply before resending the response to the
server. This setting is not configurable.)
Guest VLAN
None specified.
Inaccessible authentication bypass
Disabled.
Restricted VLAN
None specified.
Authenticator (switch) mode
None specified.
MAC authentication bypass
Disabled.
IEEE 802.1x Authentication Configuration Guidelines
These section has configuration guidelines for these features:
•
IEEE 802.1x Authentication, page 10-22
•
VLAN Assignment, Guest VLAN, Restricted VLAN, and Inaccessible Authentication Bypass, page
10-23
•
MAC Authentication Bypass, page 10-24
IEEE 802.1x Authentication
These are the IEEE 802.1x authentication configuration guidelines:
•
When IEEE 802.1x authentication is enabled, ports are authenticated before any other Layer 2 or
Layer 3 features are enabled.
•
If you try to change the mode of an IEEE 802.1x-enabled port (for example, from access to trunk),
an error message appears, and the port mode is not changed.
•
If the VLAN to which an IEEE 802.1x-enabled port is assigned changes, this change is transparent
and does not affect the switch. For example, this change occurs if a port is assigned to a RADIUS
server-assigned VLAN and is then assigned to a different VLAN after re-authentication.
If the VLAN to which an IEEE 802.1x port is assigned to shut down, disabled, or removed, the port
becomes unauthorized. For example, the port is unauthorized after the access VLAN to which a port
is assigned shuts down or is removed.
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Configuring IEEE 802.1x Authentication
•
The IEEE 802.1x protocol is supported on Layer 2 static-access ports, voice VLAN ports, and
Layer 3 routed ports, but it is not supported on these port types:
– Trunk port—If you try to enable IEEE 802.1x authentication on a trunk port, an error message
appears, and IEEE 802.1x authentication is not enabled. If you try to change the mode of an
IEEE 802.1x-enabled port to trunk, an error message appears, and the port mode is not changed.
– Dynamic ports—A port in dynamic mode can negotiate with its neighbor to become a trunk
port. If you try to enable IEEE 802.1x authentication on a dynamic port, an error message
appears, and IEEE 802.1x authentication is not enabled. If you try to change the mode of an
IEEE 802.1x-enabled port to dynamic, an error message appears, and the port mode is not
changed.
– Dynamic-access ports—If you try to enable IEEE 802.1x authentication on a dynamic-access
(VLAN Query Protocol [VQP]) port, an error message appears, and IEEE 802.1x authentication
is not enabled. If you try to change an IEEE 802.1x-enabled port to dynamic VLAN assignment,
an error message appears, and the VLAN configuration is not changed.
– EtherChannel port—Do not configure a port that is an active or a not-yet-active member of an
EtherChannel as an IEEE 802.1x port. If you try to enable IEEE 802.1x authentication on an
EtherChannel port, an error message appears, and IEEE 802.1x authentication is not enabled.
Note
In software releases earlier than Cisco IOS Release 12.2(18)SE, if IEEE 802.1x
authentication is enabled on a not-yet active port of an EtherChannel, the port does not
join the EtherChannel.
– Switched Port Analyzer (SPAN) and Remote SPAN (RSPAN) destination ports—You can
enable IEEE 802.1x authentication on a port that is a SPAN or RSPAN destination port.
However, IEEE 802.1x authentication is disabled until the port is removed as a SPAN or RSPAN
destination port. You can enable IEEE 802.1x authentication on a SPAN or RSPAN source port.
•
Before globally enabling IEEE 802.1x authentication on a switch by entering the dot1x
system-auth-control global configuration command, remove the EtherChannel configuration from
the interfaces on which IEEE 802.1x authentication and EtherChannel are configured.
•
If you are using a device running the Cisco Access Control Server (ACS) application for
IEEE 802.1x authentication with EAP-Transparent LAN Services (TLS) and EAP-MD5 and your
switch is running Cisco IOS Release 12.1(14)EA1, make sure that the device is running ACS
Version 3.2.1 or later.
VLAN Assignment, Guest VLAN, Restricted VLAN, and Inaccessible Authentication Bypass
These are the configuration guidelines for VLAN assignment, guest VLAN, restricted VLAN, and
inaccessible authentication bypass:
•
When IEEE 802.1x authentication is enabled on a port, you cannot configure a port VLAN that is
equal to a voice VLAN.
•
The IEEE 802.1x authentication with VLAN assignment feature is not supported on trunk ports,
dynamic ports, or with dynamic-access port assignment through a VMPS.
•
You can configure IEEE 802.1x authentication on a private-VLAN port, but do not configure
IEEE 802.1x authentication with port security, a voice VLAN, a guest VLAN, a restricted VLAN,
or a per-user ACL on private-VLAN ports.
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Configuring IEEE 802.1x Port-Based Authentication
Configuring IEEE 802.1x Authentication
•
You can configure any VLAN except an RSPAN VLAN, private VLAN, or a voice VLAN as an
IEEE 802.1x guest VLAN. The guest VLAN feature is not supported on internal VLANs (routed
ports) or trunk ports; it is supported only on access ports.
•
After you configure a guest VLAN for an IEEE 802.1x port to which a DHCP client is connected,
you might need to get a host IP address from a DHCP server. You can change the settings for
restarting the IEEE 802.1x authentication process on the switch before the DHCP process on the
client times out and tries to get a host IP address from the DHCP server. Decrease the settings for
the IEEE 802.1x authentication process (dot1x timeout quiet-period and dot1x timeout tx-period
interface configuration commands). The amount to decrease the settings depends on the connected
IEEE 802.1x client type.
•
When configuring the inaccessible authentication bypass feature, follow these guidelines:
– The feature is supported on IEEE 802.1x port in single-host mode and multihosts mode.
– If the client is running Windows XP and the port to which the client is connected is in the
critical-authentication state, Windows XP might report that the interface is not authenticated.
– If the Windows XP client is configured for DHCP and has an IP address from the DHCP server,
receiving an EAP-Success message on a critical port might not re-initiate the DHCP
configuration process.
– You can configure the inaccessible authentication bypass feature and the restricted VLAN on
an IEEE 802.1x port. If the switch tries to re-authenticate a critical port in a restricted VLAN
and all the RADIUS servers are unavailable, switch changes the port state to the critical
authentication state and remains in the restricted VLAN.
– You can configure the inaccessible bypass feature and port security on the same switch port.
•
You can configure any VLAN except an RSPAN VLAN or a voice VLAN as an IEEE 802.1x
restricted VLAN. The restricted VLAN feature is not supported on internal VLANs (routed ports)
or trunk ports; it is supported only on access ports.
MAC Authentication Bypass
These are the MAC authentication bypass configuration guidelines:
•
Unless otherwise stated, the MAC authentication bypass guidelines are the same as the IEEE 802.1x
authentication guidelines. For more information, see the “IEEE 802.1x Authentication” section on
page 10-22.
•
If you disable MAC authentication bypass from a port after the port has been authorized with its
MAC address, the port state is not affected.
•
If the port is in the unauthorized state and the client MAC address is not the authentication-server
database, the port remains in the unauthorized state. However, if the client MAC address is added to
the database, the switch can use MAC authentication bypass to re-authorize the port.
•
If the port is in the authorized state, the port remains in this state until re-authorization occurs.
Upgrading from a Previous Software Release
In Cisco IOS Release 12.1(14)EA1, the implementation for IEEE 802.1x authentication changed from
the previous release. Some global configuration commands became interface configuration commands,
and new commands were added.
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Configuring IEEE 802.1x Port-Based Authentication
Configuring IEEE 802.1x Authentication
If you have IEEE 802.1x authentication configured on the switch and you upgrade to Cisco IOS
Release 12.1(14)EA1 or later, the configuration file will not contain the new commands, and IEEE
802.1x authentication will not operate. After the upgrade is complete, make sure to globally enable
IEEE 802.1x authentication by using the dot1x system-auth-control global configuration command. If
IEEE 802.1x authentication was running in multiple-hosts mode on a port in the previous release, make
sure to reconfigure it by using the dot1x host-mode multi-host interface configuration command.
In Cisco IOS Release 12.2(25)SEE, the implementation for IEEE 802.1x authentication changed from
the previous releases. When IEEE 802.1x authentication is enabled, information about Port Fast is no
longer added to the configuration and this information appears in the running configuration:
dot1x pae authenticator
Configuring IEEE 802.1x Authentication
To configure IEEE 802.1x port-based authentication, you must enable authentication, authorization, and
accounting (AAA) and specify the authentication method list. A method list describes the sequence and
authentication method to be queried to authenticate a user.
To allow per-user ACLs or VLAN assignment, you must enable AAA authorization to configure the
switch for all network-related service requests.
This is the IEEE 802.1x AAA process:
Step 1
A user connects to a port on the switch.
Step 2
Authentication is performed.
Step 3
VLAN assignment is enabled, as appropriate, based on the RADIUS server configuration.
Step 4
The switch sends a start message to an accounting server.
Step 5
Re-authentication is performed, as necessary.
Step 6
The switch sends an interim accounting update to the accounting server that is based on the result of
re-authentication.
Step 7
The user disconnects from the port.
Step 8
The switch sends a stop message to the accounting server.
Beginning in privileged EXEC mode, follow these steps to configure IEEE 802.1x port-based
authentication:
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
aaa new-model
Enable AAA.
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Configuring IEEE 802.1x Authentication
Step 3
Command
Purpose
aaa authentication dot1x {default}
method1
Create an IEEE 802.1x authentication method list.
To create a default list that is used when a named list is not specified in
the authentication command, use the default keyword followed by the
method that is to be used in default situations. The default method list is
automatically applied to all ports.
For method1, enter the group radius keywords to use the list of all
RADIUS servers for authentication.
Note
Though other keywords are visible in the command-line help
string, only the group radius keywords are supported.
Step 4
dot1x system-auth-control
Enable IEEE 802.1x authentication globally on the switch.
Step 5
aaa authorization network {default}
group radius
(Optional) Configure the switch to use user-RADIUS authorization for all
network-related service requests, such as per-user ACLs or VLAN
assignment.
Note
For per-user ACLs, single-host mode must be configured. This
setting is the default.
Step 6
radius-server host ip-address
(Optional) Specify the IP address of the RADIUS server.
Step 7
radius-server key string
(Optional) Specify the authentication and encryption key used between
the switch and the RADIUS daemon running on the RADIUS server.
Step 8
interface interface-id
Specify the port connected to the client that is to be enabled for
IEEE 802.1x authentication, and enter interface configuration mode.
Step 9
switchport mode access
(Optional) Set the port to access mode only if you configured the RADIUS
server in Step 6 and Step 7.
Step 10
dot1x port-control auto
Enable IEEE 802.1x authentication on the port.
For feature interaction information, see the “IEEE 802.1x Authentication
Configuration Guidelines” section on page 10-22.
Step 11
end
Return to privileged EXEC mode.
Step 12
show dot1x
Verify your entries.
Step 13
copy running-config startup-config
(Optional) Save your entries in the configuration file.
Configuring the Switch-to-RADIUS-Server Communication
RADIUS security servers are identified by their hostname or IP address, hostname and specific UDP port
numbers, or IP address and specific UDP port numbers. The combination of the IP address and UDP port
number creates a unique identifier, which enables RADIUS requests to be sent to multiple UDP ports on
a server at the same IP address. If two different host entries on the same RADIUS server are configured
for the same service—for example, authentication—the second host entry configured acts as the fail-over
backup to the first one. The RADIUS host entries are tried in the order that they were configured.
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Configuring IEEE 802.1x Authentication
Beginning in privileged EXEC mode, follow these steps to configure the RADIUS server parameters on
the switch. This procedure is required.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
radius-server host {hostname |
Configure the RADIUS server parameters.
ip-address} auth-port port-number key
For hostname | ip-address, specify the hostname or IP address of the
string
remote RADIUS server.
For auth-port port-number, specify the UDP destination port for
authentication requests. The default is 1812. The range is 0 to 65536.
For key string, specify the authentication and encryption key used
between the switch and the RADIUS daemon running on the RADIUS
server. The key is a text string that must match the encryption key used on
the RADIUS server.
Note
Always configure the key as the last item in the radius-server
host command syntax because leading spaces are ignored, but
spaces within and at the end of the key are used. If you use spaces
in the key, do not enclose the key in quotation marks unless the
quotation marks are part of the key. This key must match the
encryption used on the RADIUS daemon.
If you want to use multiple RADIUS servers, re-enter this command.
Step 3
end
Return to privileged EXEC mode.
Step 4
show running-config
Verify your entries.
Step 5
copy running-config startup-config
(Optional) Save your entries in the configuration file.
To delete the specified RADIUS server, use the no radius-server host {hostname | ip-address} global
configuration command.
This example shows how to specify the server with IP address 172.20.39.46 as the RADIUS server, to
use port 1612 as the authorization port, and to set the encryption key to rad123, matching the key on the
RADIUS server:
Switch(config)# radius-server host 172.l20.39.46 auth-port 1612 key rad123
You can globally configure the timeout, retransmission, and encryption key values for all RADIUS
servers by using the radius-server host global configuration command. If you want to configure these
options on a per-server basis, use the radius-server timeout, radius-server retransmit, and the
radius-server key global configuration commands. For more information, see the “Configuring Settings
for All RADIUS Servers” section on page 9-29.
You also need to configure some settings on the RADIUS server. These settings include the IP address
of the switch and the key string to be shared by both the server and the switch. For more information,
see the RADIUS server documentation.
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Configuring IEEE 802.1x Port-Based Authentication
Configuring IEEE 802.1x Authentication
Configuring the Host Mode
Beginning in privileged EXEC mode, follow these steps to allow multiple hosts (clients) on an
IEEE 802.1x-authorized port that has the dot1x port-control interface configuration command set to
auto. This procedure is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to which multiple hosts are indirectly attached, and enter
interface configuration mode.
Step 3
dot1x host-mode multi-host
Allow multiple hosts (clients) on an IEEE 802.1x-authorized port.
Make sure that the dot1x port-control interface configuration command
set is set to auto for the specified interface.
Step 4
end
Return to privileged EXEC mode.
Step 5
show dot1x interface interface-id
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
To disable multiple hosts on the port, use the no dot1x host-mode multi-host interface configuration
command.
This example shows how to enable IEEE 802.1x authentication and to allow multiple hosts:
Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# dot1x port-control auto
Switch(config-if)# dot1x host-mode multi-host
Configuring Periodic Re-Authentication
You can enable periodic IEEE 802.1x client re-authentication and specify how often it occurs. If you do
not specify a time period before enabling re-authentication, the number of seconds between
re-authentication attempts is 3600.
Beginning in privileged EXEC mode, follow these steps to enable periodic re-authentication of the client
and to configure the number of seconds between re-authentication attempts. This procedure is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
Step 3
dot1x reauthentication
Enable periodic re-authentication of the client, which is disabled by
default.
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Configuring IEEE 802.1x Authentication
Command
Step 4
Purpose
dot1x timeout reauth-period {seconds | Set the number of seconds between re-authentication attempts.
server}
The keywords have these meanings:
•
seconds—Sets the number of seconds from 1 to 65535; the default is
3600 seconds.
•
server—Sets the number of seconds based on the value of the
Session-Timeout RADIUS attribute (Attribute[27]) and the
Termination-Action RADIUS attribute (Attribute [29]).
This command affects the behavior of the switch only if periodic
re-authentication is enabled.
Step 5
end
Return to privileged EXEC mode.
Step 6
show dot1x interface interface-id
Verify your entries.
Step 7
copy running-config startup-config
(Optional) Save your entries in the configuration file.
To disable periodic re-authentication, use the no dot1x reauthentication interface configuration
command. To return to the default number of seconds between re-authentication attempts, use the no
dot1x timeout reauth-period interface configuration command.
This example shows how to enable periodic re-authentication and set the number of seconds between
re-authentication attempts to 4000:
Switch(config-if)# dot1x reauthentication
Switch(config-if)# dot1x timeout reauth-period 4000
Manually Re-Authenticating a Client Connected to a Port
You can manually re-authenticate the client connected to a specific port at any time by entering the dot1x
re-authenticate interface interface-id privileged EXEC command. This step is optional. If you want to
enable or disable periodic re-authentication, see the “Configuring Periodic Re-Authentication” section
on page 10-28.
This example shows how to manually re-authenticate the client connected to a port:
Switch# dot1x re-authenticate interface gigabitethernet2/0/1
Changing the Quiet Period
When the switch cannot authenticate the client, the switch remains idle for a set period of time and then
tries again. The dot1x timeout quiet-period interface configuration command controls the idle period.
A failed authentication of the client might occur because the client provided an invalid password. You
can provide a faster response time to the user by entering a number smaller than the default.
Beginning in privileged EXEC mode, follow these steps to change the quiet period. This procedure is
optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
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Configuring IEEE 802.1x Authentication
Step 3
Command
Purpose
dot1x timeout quiet-period seconds
Set the number of seconds that the switch remains in the quiet state
following a failed authentication exchange with the client.
The range is 1 to 65535 seconds; the default is 60.
Step 4
end
Return to privileged EXEC mode.
Step 5
show dot1x interface interface-id
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
To return to the default quiet time, use the no dot1x timeout quiet-period interface configuration
command.
This example shows how to set the quiet time on the switch to 30 seconds:
Switch(config-if)# dot1x timeout quiet-period 30
Changing the Switch-to-Client Retransmission Time
The client responds to the EAP-request/identity frame from the switch with an EAP-response/identity
frame. If the switch does not receive this response, it waits a set period of time (known as the
retransmission time) and then resends the frame.
Note
You should change the default value of this command only to adjust for unusual circumstances such as
unreliable links or specific behavioral problems with certain clients and authentication servers.
Beginning in privileged EXEC mode, follow these steps to change the amount of time that the switch
waits for client notification. This procedure is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
Step 3
dot1x timeout tx-period seconds
Set the number of seconds that the switch waits for a response to an
EAP-request/identity frame from the client before resending the request.
The range is 5 to 65535 seconds; the default is 30.
Step 4
end
Return to privileged EXEC mode.
Step 5
show dot1xinterface interface-id
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
To return to the default retransmission time, use the no dot1x timeout tx-period interface configuration
command.
This example shows how to set 60 as the number of seconds that the switch waits for a response to an
EAP-request/identity frame from the client before resending the request:
Switch(config-if)# dot1x timeout tx-period 60
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Configuring IEEE 802.1x Authentication
Setting the Switch-to-Client Frame-Retransmission Number
In addition to changing the switch-to-client retransmission time, you can change the number of times
that the switch sends an EAP-request/identity frame (assuming no response is received) to the client
before restarting the authentication process.
Note
You should change the default value of this command only to adjust for unusual circumstances such as
unreliable links or specific behavioral problems with certain clients and authentication servers.
Beginning in privileged EXEC mode, follow these steps to set the switch-to-client frame-retransmission
number. This procedure is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
Step 3
dot1x max-reauth-req count
Set the number of times that the switch sends an EAP-request/identity
frame to the client before restarting the authentication process. The range
is 1 to 10; the default is 2.
Step 4
end
Return to privileged EXEC mode.
Step 5
show dot1x interface interface-id
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
To return to the default retransmission number, use the no dot1x max-req interface configuration
command.
This example shows how to set 5 as the number of times that the switch sends an EAP-request/identity
request before restarting the authentication process:
Switch(config-if)# dot1x max-req 5
Setting the Re-Authentication Number
You can also change the number of times that the switch restarts the authentication process before the
port changes to the unauthorized state.
Note
You should change the default value of this command only to adjust for unusual circumstances such as
unreliable links or specific behavioral problems with certain clients and authentication servers.
Beginning in privileged EXEC mode, follow these steps to set the re-authentication number. This
procedure is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
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Configuring IEEE 802.1x Authentication
Command
Purpose
Step 3
dot1x max-reauth-req count
Set the number of times that the switch restarts the authentication process
before the port changes to the unauthorized state. The range is 0 to 10; the
default is 2.
Step 4
end
Return to privileged EXEC mode.
Step 5
show dot1x interface interface-id
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
To return to the default re-authentication number, use the no dot1x max-reauth-req interface
configuration command.
This example shows how to set 4 as the number of times that the switch restarts the authentication
process before the port changes to the unauthorized state:
Switch(config-if)# dot1x max-reauth-req 4
Configuring IEEE 802.1x Accounting
Enabling AAA system accounting with IEEE 802.1x accounting allows system reload events to be sent
to the accounting RADIUS server for logging. The server can then infer that all active IEEE 802.1x
sessions are closed.
Because RADIUS uses the unreliable UDP transport protocol, accounting messages might be lost due to
poor network conditions. If the switch does not receive the accounting response message from the
RADIUS server after a configurable number of retransmissions of an accounting request, this system
message appears:
Accounting message %s for session %s failed to receive Accounting Response.
When the stop message is not sent successfully, this message appears:
00:09:55: %RADIUS-3-NOACCOUNTINGRESPONSE: Accounting message Start for session
172.20.50.145 sam 11/06/03 07:01:16 11000002 failed to receive Accounting Response.
Note
You must configure the RADIUS server to perform accounting tasks, such as logging start, stop, and
interim-update messages and time stamps. To turn on these functions, enable logging of
“Update/Watchdog packets from this AAA client” in your RADIUS server Network Configuration tab.
Next, enable “CVS RADIUS Accounting” in your RADIUS server System Configuration tab.
Beginning in privileged EXEC mode, follow these steps to configure IEEE 802.1x accounting after AAA
is enabled on your switch. This procedure is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
Step 3
aaa accounting dot1x default
start-stop group radius
Enable IEEE 802.1x accounting using the list of all RADIUS servers.
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Configuring IEEE 802.1x Authentication
Command
Purpose
Step 4
aaa accounting system default
start-stop group radius
(Optional) Enables system accounting (using the list of all RADIUS
servers) and generates system accounting reload event messages when the
switch reloads.
Step 5
end
Return to privileged EXEc mode.
Step 6
show running-config
Verify your entries.
Step 7
copy running-config startup-config
(Optional) Saves your entries in the configuration file.
Use the show radius statistics privileged EXEC command to display the number of RADIUS messages
that do not receive the accounting response message.
This example shows how to configure IEEE 802.1x accounting. The first command configures the
RADIUS server, specifying 1813 as the UDP port for accounting:
Switch(config)# radius-server host 172.120.39.46 auth-port 1812 acct-port 1813 key rad123
Switch(config)# aaa accounting dot1x default start-stop group radius
Switch(config)# aaa accounting system default start-stop group radius
Configuring a Guest VLAN
When you configure a guest VLAN, clients that are not IEEE 802.1x-capable are put into the guest
VLAN when the server does not receive a response to its EAP request/identity frame. Clients that are
IEEE 802.1x-capable but that fail authentication are not granted network access. The switch supports
guest VLANs in single-host or multiple-hosts mode.
Beginning in privileged EXEC mode, follow these steps to configure a guest VLAN. This procedure is
optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
For the supported port types, see the “IEEE 802.1x Authentication
Configuration Guidelines” section on page 10-22.
Step 3
switchport mode access
Set the port to access mode,
or
or
switchport mode private-vlan host
Configure the Layer 2 port as a private-VLAN host port.
Step 4
dot1x port-control auto
Enable IEEE 802.1x authentication on the port.
Step 5
dot1x guest-vlan vlan-id
Specify an active VLAN as an IEEE 802.1x guest VLAN. The range is 1
to 4094.
You can configure any active VLAN except an internal VLAN (routed
port), an RSPAN VLAN, a primary private VLAN, or a voice VLAN as
an IEEE 802.1x guest VLAN.
Step 6
end
Return to privileged EXEC mode.
Step 7
show dot1x interface interface-id
Verify your entries.
Step 8
copy running-config startup-config
(Optional) Save your entries in the configuration file.
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Configuring IEEE 802.1x Authentication
To disable and remove the guest VLAN, use the no dot1x guest-vlan interface configuration command.
The port returns to the unauthorized state.
This example shows how to enable VLAN 2 as an IEEE 802.1x guest VLAN:
Switch(config)# interface gigabitethernet2/0/2
Switch(config-if)# dot1x guest-vlan 2
This example shows how to set 3 as the quiet time on the switch, to set 15 as the number of seconds that
the switch waits for a response to an EAP-request/identity frame from the client before re-sending the
request, and to enable VLAN 2 as an IEEE 802.1x guest VLAN when an IEEE 802.1x port is connected
to a DHCP client:
Switch(config-if)# dot1x timeout quiet-period 3
Switch(config-if)# dot1x timeout tx-period 15
Switch(config-if)# dot1x guest-vlan 2
Configuring a Restricted VLAN
When you configure a restricted VLAN on a switchstack or a switch, clients that are
IEEE 802.1x-compliant are moved into the restricted VLAN when the authentication server does not
receive a valid username and password. The switch supports restricted VLANs only in single-host mode.
Beginning in privileged EXEC mode, follow these steps to configure a restricted VLAN. This procedure
is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
For the supported port types, see the “IEEE 802.1x Authentication
Configuration Guidelines” section on page 10-22.
Step 3
switchport mode access
Set the port to access mode,
or
or
switchport mode private-vlan host
Configure the Layer 2 port as a private-VLAN host port.
Step 4
dot1x port-control auto
Enable IEEE 802.1x authentication on the port.
Step 5
dot1x auth-fail vlan vlan-id
Specify an active VLAN as an IEEE 802.1x restricted VLAN. The range
is 1 to 4094.
You can configure any active VLAN except an internal VLAN (routed
port), an RSPAN VLAN, a primary private VLAN, or a voice VLAN as
an IEEE 802.1x restricted VLAN.
Step 6
end
Return to privileged EXEC mode.
Step 7
show dot1x interface interface-id
(Optional) Verify your entries.
Step 8
copy running-config startup-config
(Optional) Save your entries in the configuration file.
To disable and remove the restricted VLAN, use the no dot1x auth-fail vlan interface configuration
command. The port returns to the unauthorized state.
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Configuring IEEE 802.1x Port-Based Authentication
Configuring IEEE 802.1x Authentication
This example shows how to enable VLAN 2 as an IEEE 802.1x restricted VLAN:
Switch(config)# interface gigabitethernet2/0/2
Switch(config-if)# dot1x auth-fail vlan 2
You can configure the maximum number of authentication attempts allowed before a user is assigned to
the restricted VLAN by using the dot1x auth-fail max-attempts interface configuration command. The
range of allowable authentication attempts is 1 to 3. The default is 3 attempts.
Beginning in privileged EXEC mode, follow these steps to configure the maximum number of allowed
authentication attempts. This procedure is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
For the supported port types, see the “IEEE 802.1x Authentication
Configuration Guidelines” section on page 10-22.
Step 3
switchport mode access
Set the port to access mode,
or
or
switchport mode private-vlan host
Configure the Layer 2 port as a private-VLAN host port.
Step 4
dot1x port-control auto
Enable IEEE 802.1x authentication on the port.
Step 5
dot1x auth-fail vlan vlan-id
Specify an active VLAN as an IEEE 802.1x restricted VLAN. The range
is 1 to 4094.
You can configure any active VLAN except an internal VLAN (routed
port), an RSPAN VLAN, a primary private VLAN, or a voice VLAN as
an IEEE 802.1x restricted VLAN.
Step 6
dot1x auth-fail max-attempts max
attempts
Specify a number of authentication attempts to allow before a port moves
to the restricted VLAN. The range is 1 to 3, and the default is 3.
Step 7
end
Return to privileged EXEC mode.
Step 8
show dot1x interface interface-id
(Optional) Verify your entries.
Step 9
copy running-config startup-config
(Optional) Save your entries in the configuration file.
To return to the default value, use the no dot1x auth-fail max-attempts interface configuration
command.
This example shows how to set 2 as the number of authentication attempts allowed before the port moves
to the restricted VLAN:
Switch(config-if)# dot1x auth-fail max-attempts 2
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Configuring IEEE 802.1x Port-Based Authentication
Configuring IEEE 802.1x Authentication
Configuring the Inaccessible Authentication Bypass Feature
You can configure the inaccessible bypass feature, also referred to as critical authentication or the AAA
fail policy.
Beginning in privileged EXEC mode, follow these steps to configure the port as a critical port and enable
the inaccessible authentication bypass feature. This procedure is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
radius-server dead-criteria time time
tries tries
(Optional) Set the conditions that are used to decide when a RADIUS
server is considered unavailable or dead.
The range for time is from 1 to 120 seconds. The switch dynamically
determines the default seconds value that is 10 to 60 seconds.
The range for tries is from 1 to 100. The switch dynamically determines
the default tries parameter that is 10 to 100.
Step 3
radius-server deadtime minutes
(Optional) Sets the number of minutes that a RADIUS server is not sent
requests. The range is from 0 to 1440 minutes (24 hours). The default is
0 minutes.
Step 4
radius-server host ip-address
[acct-port udp-port] [auth-port
udp-port] [key string] [test username
name [idle-time time]
[ignore-acct-port] [ignore-auth-port]]
(Optional) Configure the RADIUS server parameters by using these
keywords:
•
acct-port udp-port—Specify the UDP port for the RADIUS
accounting server. The range for the UDP port number is from 0 to
65536. The default is 1646.
•
auth-port udp-port—Specify the UDP port for the RADIUS
authentication server. The range for the UDP port number is from 0
to 65536. The default is 1645.
Note
•
Note
You should configure the UDP port for the RADIUS accounting
server and the UDP port for the RADIUS authentication server to
nondefault values.
key string—Specify the authentication and encryption key for all
RADIUS communication between the switch and the RADIUS
daemon.
You can also configure the authentication and encryption key by
using the radius-server key {0 string | 7 string | string} global
configuration command.
•
test username name—Enable automated testing of the RADIUS
server status, and specify the username to be used.
•
idle-time time—Set the interval of time in minutes after which the
switch sends test packets to the server. The range is from 1 to
35791 minutes. The default is 60 minutes (1 hour).
•
ignore-acct-port—Disable testing on the RADIUS-server
accounting port.
•
ignore-auth-port—Disable testing on the RADIUS-server
authentication port.
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Configuring IEEE 802.1x Port-Based Authentication
Configuring IEEE 802.1x Authentication
Step 5
Command
Purpose
dot1x critical {eapol | recovery delay
milliseconds}
(Optional) Configure the parameters for inaccessible authentication
bypass:
eapol—Specify that the switch sends an EAPOL-Success message when
the switch successfully authenticates the critical port.
recovery delay milliseconds—Set the recovery delay period during
which the switch waits to re-initialize a critical port when a RADIUS
server that was unavailable becomes available. The range is from 1 to
10000 milliseconds. The default is 1000 milliseconds (a port can be
re-initialized every second).
Step 6
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
For the supported port types, see the “IEEE 802.1x Authentication
Configuration Guidelines” section on page 10-22.
Step 7
dot1x critical [recovery action
reinitialize | vlan vlan-id]
Enable the inaccessible authentication bypass feature, and use these
keywords to configure the feature:
•
recovery action reinitialize—Enable the recovery feature, and
specify that the recovery action is to authenticate the port when an
authentication server is available.
•
vlan vlan-id—Specify the access VLAN to which the switch can
assign a critical port. The range is from 1 to 4094.
Step 8
end
Return to privileged EXEC mode.
Step 9
show dot1x [interface interface-id]
(Optional) Verify your entries.
Step 10
copy running-config startup-config
(Optional) Save your entries in the configuration file.
To return to the RADIUS server default settings, use the no radius-server dead-criteria, the no
radius-server deadtime, and the no radius-server host global configuration commands. To return to
the default settings of inaccessible authentication bypass, use the no dot1x critical {eapol | recovery
delay} global configuration command. To disable inaccessible authentication bypass, use the no dot1x
critical interface configuration command.
This example shows how to configure the inaccessible authentication bypass feature:
Switch(config)# radius-server dead-criteria time 30 tries 20
Switch(config)# radius-server deadtime 60
Switch(config)# radius-server host 1.1.1.2 acct-port 1550 auth-port 1560 key abc1234 test
username user1 idle-time 30
Switch(config)# dot1x critical eapol
Switch(config)# dot1x critical recovery delay 2000
Switch(config)# interface gigabitethernet 1/0/1
Switch(config)# radius-server deadtime 60
Switch(config-if)# dot1x critical
Switch(config-if)# dot1x critical recovery action reinitialize
Switch(config-if)# dot1x critical vlan 20
Switch(config-if)# end
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Configuring IEEE 802.1x Port-Based Authentication
Configuring IEEE 802.1x Authentication
Configuring IEEE 802.1x Authentication with WoL
Beginning in privileged EXEC mode, follow these steps to enable IEEE 802.1x authentication with WoL.
This procedure is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
For the supported port types, see the “IEEE 802.1x Authentication
Configuration Guidelines” section on page 10-22.
Step 3
dot1x control-direction {both | in}
Enable IEEE 802.1x authentication with WoL on the port, and use these
keywords to configure the port as bidirectional or unidirectional.
•
both—Sets the port as bidirectional. The port cannot receive packets
from or send packets to the host. By default, the port is bidirectional.
•
in—Sets the port as unidirectional. The port can send packets to the
host but cannot receive packets from the host.
Step 4
end
Return to privileged EXEC mode.
Step 5
show dot1x interface interface-id
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
To disable IEEE 802.1x authentication with WoL, use the no dot1x control-direction interface
configuration command.
This example shows how to enable IEEE 802.1x authentication with WoL and set the port as
bidirectional:
Switch(config-if)# dot1x control-direction both
Configuring MAC Authentication Bypass
Beginning in privileged EXEC mode, follow these steps to enable MAC authentication bypass. This
procedure is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
For the supported port types, see the “IEEE 802.1x Authentication
Configuration Guidelines” section on page 10-22.
Step 3
dot1x port-control auto
Enable IEEE 802.1x authentication on the port.
Step 4
dot1x mac-auth-bypass [eap]
Enable MAC authentication bypass.
(Optional) Use the eap keyword to configure the switch to use EAP for
authorization.
Step 5
end
Return to privileged EXEC mode.
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Configuring IEEE 802.1x Port-Based Authentication
Configuring IEEE 802.1x Authentication
Command
Purpose
Step 6
show dot1x interface interface-id
Verify your entries.
Step 7
copy running-config startup-config
(Optional) Save your entries in the configuration file.
To disable MAC authentication bypass, use the no dot1x mac-auth-bypass interface configuration
command.
This example shows how to enable MAC authentication bypass:
Switch(config-if)# dot1x mac-auth-bypass
Configuring NAC Layer 2 IEEE 802.1x Validation
In Cisco IOS Release 12.2(25)SED or later, you can configure NAC Layer 2 IEEE 802.1x validation,
which is also referred to as IEEE 802.1x authentication with a RADIUS server.
Beginning in privileged EXEC mode, follow these steps to configure NAC Layer 2 IEEE 802.1x
validation. The procedure is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
Step 3
dot1x guest-vlan vlan-id
Specify an active VLAN as an IEEE 802.1x guest VLAN. The range is 1
to 4094.
You can configure any active VLAN except an internal VLAN (routed
port), an RSPAN VLAN, or a voice VLAN as an IEEE 802.1x guest
VLAN.
Step 4
dot1x reauthentication
Step 5
dot1x timeout reauth-period {seconds | Set the number of seconds between re-authentication attempts.
server}
The keywords have these meanings:
Enable periodic re-authentication of the client, which is disabled by
default.
•
seconds—Sets the number of seconds from 1 to 65535; the default is
3600 seconds.
•
server—Sets the number of seconds based on the value of the
Session-Timeout RADIUS attribute (Attribute[27]) and the
Termination-Action RADIUS attribute (Attribute [29]).
This command affects the behavior of the switch only if periodic
re-authentication is enabled.
Step 6
end
Return to privileged EXEC mode.
Step 7
show dot1x interface interface-id
Verify your IEEE 802.1x authentication configuration.
Step 8
copy running-config startup-config
(Optional) Save your entries in the configuration file.
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Configuring IEEE 802.1x Port-Based Authentication
Configuring IEEE 802.1x Authentication
This example shows how to configure NAC Layer 2 IEEE 802.1x validation:
Switch# configure terminal
Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# dot1x reauthentication
Switch(config-if)# dot1x timeout reauth-period server
Disabling IEEE 802.1x Authentication on the Port
You can disable IEEE 802.1x authentication on the port by using the no dot1x pae interface
configuration command.
Beginning in privileged EXEC mode, follow these steps to disable IEEE 802.1x authentication on the
port. This procedure is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Specify the port to be configured, and enter interface configuration mode.
Step 3
no dot1x pae
Disable IEEE 802.1x authentication on the port.
Step 4
end
Return to privileged EXEC mode.
Step 5
show dot1x interface interface-id
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
To configure the port as an IEEE 802.1x port access entity (PAE) authenticator, which enables
IEEE 802.1x on the port but does not allow clients connected to the port to be authorized, use the dot1x
pae authenticator interface configuration command.
This example shows how to disable IEEE 802.1x authentication on the port:
Switch(config)# interface gigabitethernet2/0/1
Switch(config-if)# no dot1x pae authenticator
Resetting the IEEE 802.1x Authentication Configuration to the Default Values
Beginning in privileged EXEC mode, follow these steps to reset the IEEE 802.1x authentication
configuration to the default values. This procedure is optional.
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
interface interface-id
Enter interface configuration mode, and specify the port to be configured.
Step 3
dot1x default
Reset the IEEE 802.1x parameters to the default values.
Step 4
end
Return to privileged EXEC mode.
Step 5
show dot1x interface interface-id
Verify your entries.
Step 6
copy running-config startup-config
(Optional) Save your entries in the configuration file.
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Configuring IEEE 802.1x Port-Based Authentication
Displaying IEEE 802.1x Statistics and Status
Displaying IEEE 802.1x Statistics and Status
To display IEEE 802.1x statistics for all ports, use the show dot1x all statistics privileged EXEC
command. To display IEEE 802.1x statistics for a specific port, use the show dot1x statistics interface
interface-id privileged EXEC command.
To display the IEEE 802.1x administrative and operational status for the switch, use the show dot1x all
[details | statistics | summary] privileged EXEC command. To display the IEEE 802.1x administrative
and operational status for a specific port, use the show dot1x interface interface-id privileged EXEC
command.
For detailed information about the fields in these displays, see the command reference for this release.
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Configuring IEEE 802.1x Port-Based Authentication
Displaying IEEE 802.1x Statistics and Status
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